An advocacy group for people abused by priests on Wednesday asked Cook County State's Attorney Anita Alvarez to launch a grand jury investigation into the Chicago-based Jesuit province.

The plea comes after a scathing addition to three men's lawsuit was filed in Circuit Court alleging that Jesuit leaders in Chicago knew that now-defrocked Catholic priest Donald McGuire was sexually abusing underage boys and that they sought to cover it up and mislead authorities.

"We want the prosecutor of Cook County to investigate whether there is sufficient evidence of crimes committed by the Jesuit superiors," said Barbara Blaine, president of the Survivors Network of those Abused by Priests (SNAP.) "It seems as though there's evidence of conspiracy (and) evidence of perjury."

The state's attorney's office has not been able to review the motion added to the lawsuit or SNAP's request and could not comment on SNAP's call for a grand jury probe, spokesman Andy Conklin said.

The Rev. Timothy Kesicki, provincial of the Chicago-Detroit Province of the Society of Jesus, or the Jesuits, said in a statement that the local province would not comment on legal proceedings concerning McGuire.

"I emphasize what we have said repeatedly, we are sorry," Kesicki said in the statement. "We are painfully aware that in the past we did not do enough to prevent abuse of children and vulnerable adults, and that we made mistakes by thinking that restrictive measures we undertook with regard to Donald McGuire would be effective. More important, we failed to listen to those who came forward and to meet their courage in dealing with Donald McGuire as we should have."

The motion for punitive damages filed Monday by three men allegedly abused by McGuire includes excerpts of letters written between Jesuit leaders that indicate they were aware of abuse.

The document alleges the Jesuit community's actions allowed McGuire to continue his sexual abuse of boys for dozens of years before he was sentenced in February 2009 to 25 years in prison.

"It's outrageous when you think of what they did to the children," Blaine said. "Why on earth they would leave more kids at risk?"